[Bug other/67092] bootstrap failure in running genpreds, libstdc++ version mismatch

["vries at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67092

--- Comment #6 from vries at gcc dot gnu.org ---
(In reply to H.J. Lu from comment #5)
> (In reply to vries from comment #4)
> > (In reply to H.J. Lu from comment #3)
> > > Only build/genpreds in stage1 should be linked with libstdc++.so.6.
> > 
> > Why?
> 
> Top level configure.ac has
> 
> [stage1_ldflags=
>  # In stage 1, default to linking libstdc++ and libgcc statically with GCC
>  # if supported.  But if the user explicitly specified the libraries to use,
>  # trust that they are doing what they want.
>  if test "$stage1_libs" = "" -a "$have_static_libs" = yes; then
>    stage1_ldflags="-static-libstdc++ -static-libgcc"
>  fi])
> AC_SUBST(stage1_ldflags)
> 
> Why doesn't it work for you?

AFAIU, this question has the premise that something is going wrong in stage1,
which is not the case in this PR, it's about stage2. So I'm not sure how to
answer this question.